CVE-2018-21205 in D7800
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an unauthenticated attacker. This affects D7800 before 1.0.1.30, EX2700 before 1.0.1.28, R6100 before 1.0.1.20, R7500 before 1.0.0.118, R7500v2 before 1.0.3.24, R7800 before 1.0.2.40, R9000 before 1.0.2.52, WN2000RPTv3 before 1.0.1.20, WN3000RPv3 before 1.0.2.50, WN3100RPv2 before 1.0.0.56, WNDR3700v4 before 1.0.2.96, WNDR4300 before 1.0.2.98, WNDR4300v2 before 1.0.0.50, and WNDR4500v3 before 1.0.0.50.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow condition that affects multiple NETGEAR networking devices, creating a significant security risk for affected deployments. The flaw exists within the web management interface of these routers and access points, allowing unauthenticated attackers to exploit the vulnerability remotely without requiring any credentials or prior access to the network. The vulnerability stems from insufficient input validation within the device's web server implementation, specifically when processing HTTP requests containing malformed data in the request parameters. This particular weakness falls under the CWE-121 category of stack-based buffer overflow, which occurs when more data is written to a buffer located on the stack than the buffer can accommodate, leading to memory corruption that can be exploited by malicious actors.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides attackers with the potential to execute arbitrary code on the affected devices. When an attacker sends a specially crafted HTTP request to the vulnerable device, the buffer overflow can overwrite adjacent memory locations including return addresses and function pointers, potentially allowing the attacker to redirect program execution flow. This type of exploitation aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to gain full control over the device's operating system. The vulnerability affects a wide range of NETGEAR routers and access points spanning multiple product lines including the D7800, R6100, R7500, R7800, R9000, and various WN series devices, with specific firmware versions indicating the scope of impacted models.
Network security professionals should recognize that this vulnerability creates a persistent threat vector since it requires no authentication and can be exploited from external networks. The attack surface is particularly concerning given that these devices are commonly deployed in home and small office environments where network segmentation is minimal or absent. The buffer overflow vulnerability creates a pathway for attackers to potentially gain root access to the device, which could then be used as a pivot point for further network infiltration or to establish persistent backdoors. Organizations should immediately implement network segmentation to isolate these devices from critical systems, disable unnecessary services, and apply the vendor-provided firmware updates as soon as possible. The vulnerability demonstrates the importance of proper input validation and memory management practices in embedded systems, as highlighted in the OWASP Top 10 2021 category A05: Security Misconfiguration, where inadequate input sanitization leads to buffer overflow conditions. Additionally, this vulnerability exemplifies the ATT&CK tactic T1190 for exploit public-facing application, where attackers target web applications with known vulnerabilities to gain initial access to network infrastructure. The affected devices represent a significant risk to network security posture and require immediate remediation through firmware updates, network monitoring for suspicious traffic patterns, and potentially temporary network isolation until patches are deployed.